Ascorbic acid does not reduce the anticancer effect of radiotherapy

Lo and behold, after continued and prolonged precautions over the use of oral antioxidants during cancer treatment that counter the pro-oxidant (cell killing) effects of radiation treatment, researchers in Japan found a high concentration of vitamin C (>75 umol) actually induced the death of cancer cells and enhanced the cell killing effect of radiotherapy. The researchers suggest further study and say there is no harm done when vitamin C therapy is simultaneously administered with radiation treatment.  See abstract below:

FULL TEXT:  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5244771/

Biomed Rep. 2017 Jan;6(1):103-107. doi: 10.3892/br.2016.819. Epub 2016 Nov 29.

Ascorbic acid does not reduce the anticancer effect of radiotherapy.

Hosokawa Y1, Saga R1, Monzen S1, Terashima S1, Tsuruga E1.

Department of Radiation Science, Graduate School of Health Sciences, Hirosaki University, Hirosaki, Aomori 036-8564, Japan
Correspondence to: Professor Yoichiro Hosokawa, Department of Radiation Science, Graduate School of Health Sciences, Hirosaki University, 66-1 Honcho, Hirosaki, Aomori 036-8564, Japan, E-mail: pj.ca.u-ikasorih.cc@awakosoh

Abstract

The present study hypothesized that the therapeutic use of ascorbic acid (AsA) in combination with radiation may reduce therapy-related side effects and increase the antitumor effects. The aim of the study was to examine the association between the scavenged activity of AsA and the biological anticancer effect of hydroxyl (OH) radicals generated by X-ray irradiation. Cell survival, DNA fragmentation of human leukemia HL60 cells and the amount of OH radicals were investigated following X-ray irradiation and AsA treatment. The number of living cells decreased, and DNA fragmentation increased at AsA concentrations >1 mM. Electron spin resonance spectra revealed that X-ray irradiation generated OH radicals, which were scavenged by AsA at concentrations >75 µM. The AsA concentration inside the cell was 75 µM when cells underwent extracellular treatment with 5 mM AsA, which significantly induced HL60 cell death even without irradiation. No increase in the number of viable HL60 cells was observed following AsA treatment with irradiation when compared to irradiation alone. In conclusion, the disappearance of the radiation anticancer effects with AsA treatment in combination with radiotherapy for cancer treatment is not a cause for concern.

KEYWORDS:

X-ray irradiation; ascorbic acid; cell death; hydroxyl radical; radical scavenger

PMID:

28123717

PMCID:

PMC5244771

DOI:

10.3892/br.2016.819

In conclusion, treating cancer cells with high extracellular concentrations of AsA (>5 mM) could achieve an intracellular AsA concentration level of 75 µM, leading to scavenging of ·OH generated with X-ray irradiation. However, treatment with the high extracellular concentrations of AsA alone directly induced cancer cell death. As aforementioned, the disappearance of radiation anticancer effects with AsA treatment in combination with radiotherapy for cancer treatment is not a concern. Previously, clinical trials on the effects of high-dose intravenous AsA on patients with cancer have been performed. We hypothesize that a clinical trial to evaluate the high-dose intravenous AsA combined with radiotherapy in patients with cancer will be launched in the near future.

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